Optometroscope.



6 SHEETS-SHEET 2.

Patented Dec. 28, 1909.

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M. W. GANTT. OPTOMETROSGOPE.

llIlllllllllllll"Illllllill EHIIIIIIIIII APPLICATION FILED AUG. 13,1908.

M. W. GANTT. OPTOMETROSGOPE. APPLIOATION EILBDVAUG. 13, 1908.

944,853, Patented Dec. 28, 1909.

6 SHEETSSHEET 3.

M. W. GANTT. OPTIOMBTROSGOPE. APPLICATION rum) AUG. 13, ms.

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M. W. GANTT.

OPTOMETROSCOPE.

APPLICATION FILED AUG. 13, 1908.

944,853. Patented Dec.28, 1909.

s sums-sum 5.

UNITED STATES PATENT OFFICE.

MARK W. GANTT, OF ATHENS, GEORGIA, ASSIGNOR 0F ONE-HALF T0 JOHN G.

GOUSAR, OF ATHENS, GEORGIA.

OPTOMETROSCOPE.

- Specification of Letters Patent.

Patented Dec. 28, 1909.

Application filed August 13, 1908. Serial No. 448,387.

To all whom it may concern:

Be it known that I, Mann GANTT, a citizen of the United States, residingat Athens, in the county of Clarke and State of Georgia, have inventednew and useful Improvements in Optometroscopes, of which the followingis a specification.

My present invention relates to improvements in instruments for testingthe eyesight to determine the refractive conditions thereof, and it hasfor its object primarily to provide an improved instrument of thischaracter wherein all the tests employed by oculists and Opticians maybe conducted with the greatest facility by means of the singleinstrument and wherein the results are indicated upon scales which maybe read directly by the oculist or optician in making up theprescription for the eyeglasses, and the apparatus also facilitates,examinations of the eye by the use of such instruments as theophthalmoscope and retinoscope to determine the condition for treatmentof illhealth, or causes other than refractive.

Another object of the invention is to provide an instrument of thischaracter whereby the refractive conditions of the eye, if any, may bequickly and accurately ascertained by the relative adjustment of pairsof plus and minus lenses, which lenses when placed together neutralizeone another and when separated at different distances act the same ineffect as the substituting of various lenses of different knownstrengths before the eye under test, thereby disclosing the myopic,hypermetroid, astigmatic or other refractive conditions of the eye, anindicator being operatively connected to the movable lens for.indicating directly the dioptric strength of the lens necessary tocorrect the refractive error of the eye.

Another object of the invention is to provide an instrument of the kinddescribed which embodies pairs of plus and minus cylindrical lenseswhich are capable of being.

readily manipulated for the purpose of determining the astigmaticconditions of the eye, the said cylindrical lenses being capable ofbeing separated before the eye under test so as to determine thedioptric strength, and are rotatable in order that the meridian of theastigmatism may be located, and the axes of lenses placed to correct thesame.

Further objects of the invention are to provide an instrument of thischaracter which is provided with a detachable extension or section whichis adapted to form a continuation of the primary section, and bothsections are provided with a track upon which a chart is slidable, saidchart being adapted for use in making tests to determine theaccommodation of the eyes of the patient, also to provide an instrumentof this character provided with an improved hood adapted to be fitted tothe face of the patient, which hood is provided with a frame adapted toreceive test lenses which may be-readily inserted before the eye of thepatient in order to test the refractive conditions thereof after themanner of the usual trial frame, or, such lenses as may be indicated bythe scales in the preceding tests may be inserted in order to verify theresults of the original tests, the lens receiving frame of the hoodbeing provided with rotatable lens holders to accommodate and properlyposition cylindrical lenses before the eyes of the patient, and it alsoprovides a similar hood upon the opposite end of the instrument toreceive the face of the operator when making tests with anophthalmoscope or retinoscope, the said hood serving to cut off alllight from the interior of the instrument so that the -muscles of thepatients eye are relaxed, and this hood is also adapted to receivelenses to take the place of the glasses of the operator and such lensesas may be necessary to give a better view of the fundus in makingexaminations.

To these and other ends, the invention consists in certain improvements,and combinations and arrangements of parts, all as will be hereinaftermore fully described, the novel features being pointed out particularlyin the claims at the end of the specifi cation.

In the accompanying drawing: Figure 1 represents a longitudinal sectionof an optical instrument constructed in accordance with my presentinvention, the section being taken in a vertical plane; Fig. 2 alsorepresents an axial section of the instrument shown in Fig. l, thesection being taken in a horizontal plane; Fig. 3 represents an endelevation of the instrument as viewed from the left in Figs. 1 and 2;Fig. 4C is an end elevation of the instrument as viewed from the rightin Figs. 1 and 2, the cover or closure at the rear of the instrumentbeing removed; Fig. 5 is a plan view partly in section showing theextension section fitted to the instrument; Figs. 6 to 9, inclusive, aredetail views of one of the lens holders; Fig. 10 represents a transversesection of the instrument shown in Fig. 5 taken upon the line 101Othereof; Fig. 11 is a detail sec tional view of the chart carrier whichis adapted to be used in connection with the apparatus shown in Fig. 5for making the presbyopic tests; Fig. 12 is a detail view of asupporting bracket for the shaft; Fig. 13 is a detail view of theshifting member for the movable lens holder; and Figs. 1a and 15illustrate a stationary chart holder as viewed from the front and rear.

Similar parts are designated by the same reference characters in theseveral views.

In the accompanying drawing, I have shown one specific embodiment of theinven tion which is capable of use in performing all the ordinary testsemployed by oculists and Opticians in determining the refractive errorsof the eye and for examining the conditions of the eye by the aid of theophthalmoscope and retinoscope, but it will be understood that theinvention is not necessarily so limited and that certain modificationsin the detail construction and arrangement of the parts and that certaincharts and other appliances may be used in connection with theinstrument as may be found desirable or necessary.

In the present instance, the instrument comprises generally a mainsection which may be supported on a table or stand by means of astandard 1 which is attached to a tubular casing 2, the latter beingclosed at its forward end by means of a plate 3 which is fitted to thetubular casing by means of a flange 4:, and the upper half of this frontplate preferably projects beyond the periphery of the tubular casing toprovide a segmental scale board 5 which is in approximately the form ofa half circle, the rear end of the casing being substantially closed bya cover or closure 6, the latter being detachably connected to the mainsection by any suitable means, such for instance, as an internal flange7, the cover being provided with an opening 8 for a purpose to behereinafter described.

Mounted centrally within the tubular casing is a shaft 9 having itsforward end jour naled in a bearing 10 formed in the front plate and hasa spur gear 11 fixed to rotate therewith. This spur gear is arranged tocooperate with a pinion 12 which is revolubly mounted upon the frontplate, this pinion in turn cooperating with a ring gear 13 which ismounted to revolve in an annular channel 14: formed in the flange 4t andis provided with a pointer or hand 15 which projects radially from thering and is arranged to cooperate with a set of scales 16', 17 and 18arranged on the rear side of the scale board ence to the respectivescales.

5, rotation of the shaft causing a corresponding movement of theindicator with refer- This shaft is provided with a helical groove orkey-way 19 in which a key or projection 20 operates, this key orprojection being mounted upon a reciprocatory rack 21 which is attachedat its forward end to the lens shifting member and cooperates at itsrear end with an operating pinion 23, the latter being provided with ashaft which is journaled in a pair of bearing arms 2% formed upon theshaft supporting standard 25, and the shaft of the pinion extendsthrough a bearing 26 to the exterior of the casing and is provided witha crank 27 by means of which it may be operated, rotation of the crankcausing a longitudinal movement of the rack 21, and the rectilinearmovement of the key or proj ection 20 in traversing the helical key-wayor groove 19 of the shaft will cause rotation of the latter. The shaftsupporting standard 25 is secured to the bottom of the casing at a pointin proximity to the rear end thereof, and a sleeve 28 surrounds theshaft 9 and is slidable longitudinally of the shaft according to thecorresponding longitudinal movement of the rack 21. This sleeve,however, is not rotatable and, in order to prevent rotation thereof, itis provided with a longitudinal key-way 29 with which a setscrew orequivalent device 30 secured to the bearing standard 25 cooperates, thissetscrew permitting a longitudinal movement of the sleeve through theshaft supporting standard, although preventing rotation of the sleeve.

Fitted on the forward end of the sleeve 28 is a movable lens holder 31which is preferably a segmental disk or frame of substantiallysemi-circular form in order that it may be shifted into a position tobring the lenses therein into alinement with the line of vision, or, itmay be wholly moved out of the line of vision. This lens holder isprovided with a hub 32 which is rotatable upon the sleeve between theend flange 33 and the shoulder 3 1 thereon. Fixed to and rotatable withthe lens holder is a gear 35 which serves to turn the lens holder eitherinto operative 0r inoperative positions with respect to the line ofvision, this gear cooperating with a gear 36 fixed to a shaft 37 thelatter being mounted to slide longitudinally through the hub of a bevelgear 38 which is journaled in the standard 25 but is keyed to rotatewith said gear, the gear 38 being arranged to cooperate with a gear 39mounted upon a shaft 40, the said shaft extending through a bearing tothe exterior of the casing and is provided with a crank 41 by means ofwhich it may be rotated, said crank being provided with an indicatorwhich is arranged to cooperate with a suitably gra duated scale 12surrounding the axis of the crank at the exterior of the casing. Byrotating the crank 41, the shaft- 37 will be correspondingly rotatedirrespective of the relative longitudinal position of the mov able lensholder 31, and the rotary movement of the shaft 37 will be transmittedthrough the gears and 36 to the lens holder which will be thereby causedto turn about the central shaft 9 as an axis. This lens holder is fittedpreferably with a pair of plus and minus spherical lenses 43 and M,respectively, and also a pair of plus and minus cylinder lenses 45 and4G and, by rotating this lens holder about the central shaft as an axis,it is possible to accurately position each lens therein in alinementwith the line of vision of the patients eye, the scale 4L2 beingappropriately graduated so as to indicate to the operator which lens ofthe holder is positioned before the eye.

The spherical lenses may be fitted in the holder in any appropriatemanner, such for instance, as by means of a flanged sleeve 47 which iscontained in an aperture &8 in the holder and is threaded to receive alens securing ring 49, the lens being clamped between this ring and theadjacent end of the flanged sleeve, the flange 50 of the sleeve engagingthe rear side of the lens holder. The cylinder lenses, however, arerotatably mounted in the holder in order that the meridian or axis ofthe cylinder may be adjusted to correspond to the meridian of theastigmatic error of the eye under test, and for this purpose, theflanged sleeve 51 is rotatably fitted in the aperture in the holder andthe flange 52 thereon constitutes a spur gear, the gear on the sleevecarrying each cylinder lens meshing with a pair of pinions 53 and 5%which in turn mesh with a central gear 55, the latter being revolublymounted upon the hub 32 of the lens holder. Rotation of the central gear55 will cause cor responding rotation of the respective cylinder lenses,and the necessary rotary movement is imparted to the gear 55 by means ofa cooperating gear 56 which is fixed to a shaft 57 journaled in abearing 58 formed on the lens shifting member 22, and this shaft 57 isslidable longitudinally through a bevel gear jonrnaled in a bearing 60on the standard 25 but is keyed to rotate with the said bevel gear, thelatter meshing with a cooperating bevel gear 61 which is mounted on ashaft 62 which shaft extends through a bearing 63 to the exterior of thecasing, the outer end of the shaft being provided with an operatingcrank 64 and the crank in turn is provided with a dial or scale 65, thelatter being graduated in degrees which indicate the angular position ofthe axes of each cylinder lens. The upper end of the lens shiftingmember 22 is provided with a ring (56 which surrounds the hub 32 of thelens frame and engages between the gears 35 and 55, the lower end ofthis member being provided with a notch 67 which cooperates with alongitudinally extending track 68 arranged on the bottom of the casingso as to insure a rectilinear movement of the lens shifting member asthe operating rack 21 is reciprocated, a corresponding reciprocatingmovement being imparted to the lens shifting member which will operateto shift the movable lens holder 31 axially of the instrument.

A stationary lens holder ()9 is fitted with plus and minus spherical andcylindrical lenses similar to those fitted in the movable holder abovedescribed, the lens holder (39 being provided with a hub or sleeve 70which is loosely revoluble on the forward end of the shaft 9 and has abevel gear 71 fixed thereto, this bevel gear cooperating with a bevelgear 72 which has an operating crank 73 which is arranged at theexterior of theinstrinnent casing and is provided with a pointer whichis arranged to cooperate with a suitably graduated dial 74:, this crank73 operating through the bevel gears '71 and 72 to rotate the lensholder 69 so as to bring the desired lens therein into the line ofvision of the patient or to carry the lens holder out of the line ofvision, the position of the lens holder being ascertained by referenceto the dial 7st. Mounted loosely upon the hub 70 a sleeve 75 providedwith a spur gear 76 and bevel gear 77, the spur gear cooperating with apair of pinions 78 which in turn mesh with the 79 formed on therevoluble frames supporting the two cylinder lenses, and a bevel gear 80cooperates with the bevel gear 77, the bevel gear 80 being provided witha crank 81 which is arranged at the exterior of the instrument casingand is provided with an indicator or hand which is arranged to cooperatewith a dial 82, the latter being graduated in degrees and serving toindicate the angular position of the axes of the two cylinder len es. Byrotating the crank 81, a corresponding rotary motion is imparted to thetwo cylinder lenses contained in the holder.

The necessary illumination is transmitted to the interior of theii'istrument casing through a socket 83 which is fitted in one side ofthe casing at such an angle that its axis passes through the aperture 8in the rear closure or cover 6, a lamp or other illuminating device 84?being provided which has .a tubular sleeve 85 which is adapted todetachably engage the socketas shown in Fig. 2. In testing theaccommodation of the eye, an extension section 86 is detachablyconnected to the rear end of the main section 2, as shown in Fig. 5, thecover (3 being removed and the internal flange 7 serving to provide asecure and light-tight joint between the sections, and the cover 6 or aduplicate thereof is attached to the rear end of the extension section.This latter section is also provided with a socket 87 which is aduplicate of the socket 83, and the attaching sleeve 85 of theilluminating device is adapted to interchangeably fit either of the saidsockets, the socket 87 being arranged in such angular relation to theinstrument that the beam of light from the illuminating device will passthrough the opening in the rear cover. This extension section isprovided in the top thereof with a longitudinally extending track 88which is arranged to register with a similar track 89 provided in themain section, and a slide 90 is shiftable longitudinally on the saidtrack and is provided with an annular holder 91 to receive anappropriate chart 92. In the present instance, the annular holder isprovided with a transverse slot 93, a door 103 being provided in theinstrument casing through which the charts may be applied to the saidchart holder. This chart holder is located in axial alinement with thesight aperture 97 which is formed in the front plate of the instrumentabove the central shaft thereof, and the distance of the chart from theeye may be adjusted by means of a rod 98 which is operable through therear cover and is suitably graduated preferably in inches and dioptricswhereby the distance of the chart from the eye may be quickly noted bythe Optician.

On the front and rear of the instrument are mounted a pair of hoods 102and 104 which are adapted to fit the faces of the patient and operator,respectively, so as to exclude light from the interior of the instrumentand thereby enable .the examinations to be conducted while the musclesof the patients eye are relaxed. In order to secure this result, eachhood is preferably composed of a central section 105 and a pair ofslidable or otherwise adjustable outer sections 106 and 107, the lattersections being adjustable toward and from the central section in orderthat the hood may conform closely to the contour of the face of thepatient and are normally pressed inwardly to engage the face by thesprings 101, the edges of the sections being preferably fitted with feltor other relatively soft or yielding material in order to provide alight seal. Each hood is mounted upon a frame 108, the rear portion ofwhich is provided with upper and lower flanges 109 which are slidable inhorizontal guides 110 in order that the hood may occupy a position sothat either eye of the patient or operator may be arranged centrallyabove the shaft 9, or, the two eyes of the patient or operator may belocated equi distantly upon opposite sides of a perpendicular passingthrough the central shaft 9. A shifting handle 99 is provided for thehood 102 and is adapted to cooperate with suitable catches 100 wherebythe hood may be held in either a central position, or a position ateither side thereof. Vithin each hood are mounted a pair of eye-pieces111 and 112 which are arranged to register with the two eyes of thepatient or operator, and a set of lens holders 113, 11 1 and 115 arearranged in alinement with each eye-piece. The lens holders 113 and11-1- are adapted to receive spherical lenses while the holder 115 isadapted to receive cylinder lenses.

In order to enable the cylinder lenses to be rotated so that the axisthereof may corre spond properly with the axis of astigmatism of theeye, this holder is rotatably mounted within the frame 108 and isprovided at its rear end with a bevel gear 116, the bevel gears of therespective lens holders cooperating with bevel pinions 117 and 118 whichare provided respectively with the operating heads 119 and 120, both ofwhich are preferably operable from the same side of the machine forconvenience, as shown in Fig. 3.

In making certain tests, it is useful to employ a stationary chartholder 121 which is preferably mounted within the rear portion of theextension section 86 of the instrument, this holder in the presentinstance comprising a casing which is provided with a standard 122 whichrests upon the bottom of the casing of the instrument and the upperportion of the chart holder is provided with an aperture 123 throughwhich the adjusting rod 98 of the movable chart holder may 0perate. Atthe upper and lower portions of the stationary chart holder arerevolubly mounted a pair of rolls or spools 12st and 125 upon which iswound a strip 120. This strip has printed thereon suitable objects orcharts to enable various tests to be conducted therewith, this chartbeing adapted to be viewed through an aperture 127 which is arranged inthe casing of the chart holder in alinement with the line of vision.

It is generally preferable to provide the mo able strip with one or morepictures so as to enable the picture test to be performed. test type,muscular charts, colorblind charts and also astigmatic charts and, inorder to locate the meridian of the astigmatism, an annular gear 128 isjournaled upon the chart casing so as to surround the sight aperturetherein and is provided with a pointer 129 which is revoluble about theastigmatic chart at the will of the operator. In order to facilitate theadjustment of this pointer, the same is operable from the terior of theinstrument, a gear 1.30 being employed in the present instance whichcooperates with the annular gear 128 and also provided with a beveledportion which cooperates with a bevel gear 131, the latter being fixedto a shaft 132 which is jourualed upon the instrument casing and isprovided with a crank 133 which is arranged at the exterior of thecasing, a suitably graduated dial 134 being arranged also upon theexterior of the casing and is graduated in degrees with which the crankcooperates as an indicator for designating the angular position of thepointer with reference to the astigmatic chart. The different chartsupon the flexible strip may also be brought into the line of vision bymeans of a crank 135 which is arranged at the exterior of the instrumentand cooperates with a suitable dial 136 which serves to indicate whichchart occupies a position in the line of vision. This crank is mountedupon a shaft 137 having a gear wheel 138 fixed thereto and whichcooperates with a pair of gears 139 and 140 which are fixed to turn withthe respective rolls or spools. This flexible strip of the chart holderis also preferably provided with an aperture in order to permit anunobstructed passage of light therethrough in performing certain tests.

In order to permit the presbyopic test to be conducted with facility,the movable lens holder 31 is provided at points immediately adjacent tothe spherical lenses with a pair of chart-receiving holders 141 and 142into which appropriate charts may be slipped through the door 108 in theforward section of the instrument casing, these charts occupyingpositions next to the respective lenses,

the stationary lens holder being so adjusted that light from the rear ofthe instrument may be reflected directly through a clear opening thereinso as to illuminate whichever chart upon the holder 21 is brought intothe line of vision.

In order to permit tests by the aid of the ophthalmoscope andretinoscope, the rear hood is provided with an opening 1&3 into whichthe appropriate instrument may be inserted, the instrument occupying aposition in alinement with the line of vision and in such a position asto receive a beam of light from the illuminating device when placed uponthe socket 87. Over each eyepiece of the hood is also arranged a scale,the scales 144 and 145 being shown in Fig. 3 which extend to an angle of180, these scales serving to indicate the angular position occupied bythe cylindrical lenses which are mounted in the rotatable lens holdersof the hood.

An optical instrument constructed in accordance with my invention iscapable of use in connection with practically all the tests which areusually employed by oculists and opticians in determlning the refractiveerrors of the eyesight. In making the usual examination of the retina ofthe eye by the aid of the retinoscope, the illuminating device isapplied to the socket 83 of the main section, and a retinoscope isplaced in the opening 8 of the rear cover 6. The patient is placed atthe left hand end of the instrument with the hood applied to the face,and

the beam of light from the illuminating device is reflected by theretinoscope into the eye under test. In this manner, the fundus of theeye may be readily examined and the conditions thereof observed, theinterior of the instrument being dark except for the beam of light fromthe illuminating device and the retinoscope. By placing the appropriatelenses in one of the holders adjacent the hood, or, by turning theforward lens holder 69 into a position to bring one of the convex lensesthereof in alinement with the eye, the retina may be magnified so as tofacilitate the examination.

In order to perform the usual test by the aid of the ophthalmoscope, therear section 86 of the instrument is removed and the rear cap carryingthe hood for the operator is attached to the rear end of the easingsection 2, the illuminating device being transferred from the rearsocket 87 to the forward socket 83 and the ophthalmoscope being insertedin the aperture or opening 143. By placing an appropriate lens in one ofthe holders of the hood next to the patients eye under examination, orby turning the forward lens holders 39 and 31 so as to bring theappropriate lenses into the line of vision, an examination of the eyemay be obtained by the indirect method.

In conducting the presbyopic test, the stationary lens holder 69 only isemployed, it being rotated so as to bring the plus spherical lens intothe line of vision. The patient is instructed to view a chart which isplaced in one of the holders of the lens holder 31, the flexible stripin the stationary chart holder being adjusted so as to bring the clearspace or opening into the line of vision so that light may be reflectedthrough the same and upon the chart in the holder 31. fractive defectare registered on a scale in the same manner as in the dioptric test.

In order to perform the usual accommodation test, the extension section82 is fitted to the rear end of the instrument, and an appropriate chartis placed in the slide 91. By shifting the slide while the chart isunder observation by the patient, the accommodation of the eye may bequickly determined, and the reading distance may be found by referenceto the scale upon the graduated rod 98 which serves to operate theslide. hen the slide is at the rearmostend of the instrument, it ispreferably at a dis tance of, say, forty inches and, by fitting theilluminating device to the rear socket 87, the chart will be properlyilluminated, and the test for distant reading may then be performed. Inperforming this test, the test lenses may be applied to the lens holders113, 114 and 115 in a manner similar to the use of the ordinary trialframe which,

however, is commonly employed at a dis The lenses required to correctthe re tance of twenty feet from the test type or reading matter, or, byremoving the reflector and charts out of the line of vision, the patientis allowed to look clear through the instrument and onto a chart at agiven distance and, by bringing the rotatable lens holders into service,examination is made in the same manner as in the dioptric test, only thepatient views the charts the same as in the usual 2020 test, and theregistration of lenses necessary to correct the refractive errors is thesame as dioptric test. Or, by dropping lenses into hood next patientseye, all. tests made with test case can be performed.

In conducting the dioptric test, the relatively stationary and movablelens holders 69 and 31 are preferably employed, these lens holders beingrotated so as to bring the spherical lenses thereof into the line ofvision by rotating the cranks 73 and 31, respeetively. In conductingthis test, both lens holders are initially placed in imme diateproximity or close to one another with a plus spherical lens in oneholder in alinement with a minus spherical lens in the other holder.While the patient observes the chart at the rear of the instrument, themovable lens holder 31 is shifted rearwardly by operating the crank ,7which reciprocates the rack 21. When the lens holders are in immediateproximity, the plus and minus lenses thereof neutralize one another, butas the holders are separated, the dioptric strength of the combinedlenses begins to vary, and when the movable lens holder has been shiftedinto such a position that the dioptric strength of the two lensescorrects the refractive error of the eye so that the chart may be readproperly by the patient, the appropriate scale 17 or 18 is referred toby the operator from which scale a direct reading of the dioptricstrength of the lens to be employed may be determined. The pointer orindicator 15 which cooperates with these scales is rotated in proportionto the shifting movement of the movable lens holder, the shiftingmovement of the said holder causing rotation of the indicator by meansof the key or projection 20 which operates in the helical key-way orgroove 19 of the central shaft 9, the latter serving to turn the spurwheel 11 which in turn cooperates with the pinion 12 which engages thering gear 13 upon which the pointer is mounted. One of the scales, thescale 17 in the present instance, is used when a hypermetropic conditionof the eye is to be corrected, while the other scale 18 is .read when amyopic condition of the eye is to be corrected, and in one case theminus spherical lens in the forward or stationary lens holder 69 isplaced next to the eye while in the other case the plus lens in the saidholder is to be placed next to the patients eye, a lens of oppositecurvature in each case being positioned in the line of vision by themovable holder 31. After the two holders have been separated to a pointwhere the reading matter upon the chart may be readily read by thepatient, the accommodation of the eye as to the strength of lens the eyewill accept or overcome may be tested by shifting the movable lensholder,

the scales 1'? or 18, as previously stated,

will indicate the dioptric strength of the lenses required to correctthe refractive errors of the eye, and by noting these readings, theoperator may make out the pre scription. If so desired, the prescriptionmay be verified by selecting the appropriate test lenses called for bythe scales and inserting these test lenses in the lens holdersimmediately in rear of the hood, the lens holders 31 and 69 being swungout of the line of vision so that the patient may view the chart throughthe test lenses.

In determining the astigmatic conditions of the eye, the lens holders 31and 69 are employed in a manner similar to that described in connectionwith the test for the dioptric errors, the axis of the astigmatic errorhaving been previously determined by a viewing of the astigmatic chartby the patient, and by setting the appropriate cylindrical lenses in theholders 31 and 69 at the proper angle by turning the cranks 64 and 81,both plusand minus cylinder lenses in the two holders may be broughtinto a position so that their axes coincide. Then by shifting themovable lens holder 31 rearwardly while the chart is under observationby the patient, the refractive strength of the two cylinder lenses maybe varied until it properly corrects the astigmatic error. Therearwardly shifting movement of the lens holder 39 will also in thisinstance be registered upon the appropriate scale 17 or 18, and bycombining the astigmatic correction with that for the general myopic orhypermetropic condition of the eye, the proper prescription may be madeout. In performing the tests, each eye may be brought into position forindividual test by shifting the hood first to one side of the instrumentand then to the other and, in testing the binocular vision, the hood maybe placed centrally, at which point the chart or other appropriatematter may be viewed by both eyes of the patient. The hood also 1enables a muscular test to be performed by fitting the usual prisms intothe lens holders of the hood and, if so desired, the test may beconducted solely by the aid of the hood after the manner of the usualtrial l In conducting tests by the aid of the Maddox rod chromaticlenses, or in conducting the color-blind test, or any tests whichrequire a blaze, the blaze is arranged at the rear end of the instrumentin place of the retinoscope, and all obstacles are removed from the lineof vision, this test being conducted in the same manner as with theusualtrial frame and test lens.

An optical testing instrument constructed in accordance with myinvention embodies all the requisite appliances for conducting the usualtests employed by oculists and opticians in determining the refractiveerrors of the eyesight and for examining the eye to determine theorganic conditions thereof, the instrument being closed so as to renderthe use of the usual dark room unnecessary and, by employing such an instrument, the various tests cannot only be performed with the greatestfacility, but extreme accuracy is obtainable and, moreover, as all thenecessary appliances are combined in a single instrument, the expense ofan outfit, and the labor of manipulating the parts thereof during thedifferent tests are minimized, thereby enabling the operator to obtainan accurate prescription very quickly. By using a pair of relativelyadjustable lens holders wherein plus and minus lenses are combined andadjusted according to the refractive power of the eye, an accurateresult may be quickly obtained without losing time in applying andremoving the different test lenses as commonly employed and, as theduration of the test is thus minimized, the best results are obtainable,as the entire test may be accomplished while the eye is in a normalstate, that is to say, before the eye has been strained or irritatedbecause of the fatigue of a long and trying test.

The chart holder which is adjustable at different distances also enablesthe usual tests for determining the accommodation, near and distantreading, astigmatism and the various defects to be conducted with thegreatest facility and accuracy, the results being readable directly fromthe graduated rod and scale or front end and, by using a hood havinglens holders fitted therein, the results obtained in the preceding testsmay, if so desired, be verified by inserting the trial lenses indicated,or, the eyes may be tested solely by inserting the different triallenses in the lens holders of the hood after the manner of the trialframe as generally employed, but obviating many of the objec tionsattending the use of the ordinary trial frame.

I claim as my invention 1. An optical instrument of the class de scribedcomprising an eye-piece, and a pair of lens holders having respectivelysets of plus and minus lenses therein adapted to be I l l l i broughtinto alinement with the eye-piece, one of the lens holders beingadjustable axially of the eye-piece with respect to the other holderwhile a plus lens in one holder is in alinement with a minus lens in thelenses of different powers supported thereon I and adapted to be broughtinto alineniei'lt with the eye-piece, the lens holders being relativelyadjustable axially of the eye-piece while a plus lens in one holder isin alinement with a minus lens in the other holder, and an indicator onthe exterior of the instrument for designating the refractive power ofthe combined lenses while adjusted at different relative distances fromone a nother.

An optoinetroscope comprising an eyepiece, a pair of lens holders eachhaving a pair of plus and minus lenses adapted to be brought intoalinement with the eyepiece, the holders being relatively adjustableaxially of the eye-piece while a plus lens in one holder is in alinementwith a minus lens in the other holder for testing either the myopic orhypermetropic conditions of an eye under test, and an indicator operableduring the relative axial adjustments of the lens holders for directlyindicating the refractive power of the combined lenses thereof.

4-. An optical instrument of the class described comprising aneye-piece, a pair of holders relatively adjustable axially of theeye-piece, a plus cylinder lens being mounted in one holder and a minuscylinder lens in the other holder, a relative axial adjustment of theholders serving to vary the refractive power of the combined cylinderlenses.

An optical instrument of the class described comprising a casing havingan eyepiece at one end, means for supporting a chart in alinement withthe eye-piece, a pair of lens holders relatively adjustable axially ofthe eye-piece, a plus cylinder lens rotatably mounted in one holder, aminus cylinder lens rotatably mounted in the other holder, said lensesbeing adapted to be brought into alinement with the eye-piece, and therelative axial adjustment of the holders while both lenses are inalinement with the eye-piece serving to vary the refractive power of thecombined lenses, and means for individually rotating the respectivecylinder lenses to ad just the axes thereof.

6. An optical instrument of the class described comprising a casinghaving an eyepiece at one end, means for supporting a chart incooperative relation with the eyepiece, a pair of lens holdersadjustable axially with respect to the eye-piece, a plus cylinder lensmounted rotatably in. one holder, a minus cylinder lens rotatablymounted in the other holder, said lenses being adapted to register withone another and with the axis of the eye-piece, the rela tive adjustmentof the holders axially of the eye-piece serving to vary the refractivepower of the combined lenses, means for individually rotating thecylinder lenses of the respective holders from the exterior of thecasing to adjust the axes thereof, and means for indicating the axes ofthe respective lenses.

7. An optical instrument of the class described comprising an eye-piece,a pair of lens holders relatively adjustable axially of the eye-piece,each having a pair of plus and minus cylinder lenses revolubly mountedtherein, and means common to each pair of lenses for effecting rotationthereof to adjust their axes.

S. An optical instrument of the class described comprising a casing, aneye-piece mounted at one end thereof, means for supporting a target insaid casing in cooperative relation with the eye-piece, a lens holderhaving a pair of plus and minus cylinder lenses revolubly mountedtherein each provided with a gear, means for rotating the lens holder toset either of said lenses in optical alinement with the eye-piece, anoperating gear having its axis arranged coaxially with the axis ofrotation of the lens holder and having gearing connecting it with thegears of the respective cylinder lenses, means cooperating with saidcentral operating gear for rotating the cylinder lenses in the holder,and a device for indicating the axes of the cylinder lenses.

9. An optical instrument of the class described comprising a casinghaving an eye piece at one end, a lens holder mounted within the casing,a shaft for supporting said lens holder for rotary and longitudinalmovements, a set of lenses mounted in said holder and adapted to bebrought into optical alinement with the eye-piece by a relative rotarymovement of the holder, an operating shaft connected to movelongitudinally with the said holder and operatively connected to thelatter for rotating it, and means operable from the exterior of thecasing and connected to the operating shaft irrespective of thelongitudinal position of the lens holder for effecting rotaryadjustments thereof.

10. An optical instrument of the class described comprising a casinghaving an eyepiece arranged at one end thereof, a shaft extendinglongitudinally of the casing, a non-rotatable sleeve slidablelongitudinally with respect to said shaft, a lens holder rotatable onsaid sleeve and provided with lenses adapted to be moved into opticalalinement with the eye-piece, an operating rack connected to said lensholder for reciprocating it, means operable from the exterior of thecasing and cotiperating with said rack for actuating it, and a shaftmovable longitudinally with the lens holder and provided with means forrotating the latter irrespective of its longitudinal position.

11. An optical instrument of the class described comprising asubstantially closed tubular casing having an eye-piece at one end, achart holder arranged in alinement therewith, a segmental lens holderinclosed within said tubular casing and fitted with a set of test lensesand mounted to swing into and out of optical alinement with respect tothe said eyepiece, and means arranged at the exterior of the casing forindicating which lens of the set is in operative position.

12. An optical instrument of the class described comprising a suitablecasing having an eye-piece therein, a lens holder ad justable axiallywith respect to the eyepiece, means for effecting such axial adjustmentof the lens holder, and a rotatable indicator cooperative with anappropriate scale on the exterior of thccasing and connected to rotateduring the relative axial adjustments of the lens holder for indicatingthe different longitudinal positions of the latter. a

13. An optical instrument of the class described comprising a suitablecasing having an eyepiece therein, a longitudinal shaft mounted in thecasing, a rotatable indicator connected to said shaft, a lens holderadjustable axially with respect to said shaft and having a lens holdertherein adapted to be arranged in axial alinement with the eyepiece, andmeans operable by the lens holder to cause rotation of said shaft toturn the indicator according to the longitudinal movements of theholder.

lat. An optical instrument of the class described comprising a suitablecasing having an eye-piece, a shaft journaled within the casing, a lensholder movable axially with respect to said shaft and adapted to supporta lens at different distances from the; eye-piece, a gear rotatable withthe shaft, a ring gear operatively connected to the gear of said shaft,a pointer rotatable with the ring gear, and a scale adapted to cooperatewith said pointer to designate the relative distances of the lens holderfrom the eye-piece.

15, An optical instrument of the class described comprising a suitablecasing having an eye-piece therein, a shaft journaled within the casing,a lens holder slidable longitudinally on the shaft and carrying a lensadapted to be supported at different distances from the eye-piece, meansoperable by the longitudinal movements of the lens holder for rotatingthe shaft, a gear fixed to the shaft, a ring gear surrounding the easingand carrying a pointer, a pinion connecting said ring gear to the gearupon the shaft, and a scale adapted to cooperate with said pointer.

16. An optical instrument of the class described comprising a suitablecasing having an eye-piece, a shaft journaled within the casing, asleeve surrounding and movable axially with respect to the shaft, one ofsaid parts having a helical groove therein and the other having a key orprojection to cooperate with said groove for causing relative rotationof the parts when moved longitudinally, a lens holder movablelongitudinally with said sleeve and having a lens adapted to besupported at different distances from the eye-piece, and a pointeroperatively connected to the shaft and rotatable according to thelongitudinal movements of the lens holder.

17. An optical instrument of the class described comprising a suitablecasing having an eye-piece therein, a shaft ournaled within the casingand provided with a helical keyqvay or groove, a sleeve surrounding theshaft and mo able axially thereon, the said sleeve being provided with alongitudinal key-way, a relatively fixed device arranged to cooperatewith said key-way to permit longitudinal movement of the sleeve andprevent rotary movement thereof, a lens holder movable longitudinallywith said sleeve and carrying a lens adapted to be supported atdifferent distances from the eye-piece, a key or projection movable withsaid sleeve and adapted to cooperate with the helical key-way in theshaft to effect rotary movement of the shaft during the axial movementsof the sleeve, and an inclicator operable by the rotary movements ofsaid shaft.

18. An optical instrument of the class described comprising a tubularcasing having an eye-piece at one end, a holder movable longitudinallyof the casing for supporting test lenses in alinement with saideye-piece, and a chart holder supported within the casing independentlyof said lens holder and slidable longitudinally thereof in alinementwith the said eye-piece.

19. An optical instrument of the class described comprising a tubularcasing having an eye-piece at one end, means for positioning sets oftest lenses of different powers in alinement with the said eye-piece, atrack extending longitudinally of the casing, and a chart holder guidedto operate longitudinally on said track and in alinement with theeye-piece and test lenses.

20. An optical instrument of the class described comprising a tubularcasing having an eye-piece at one end, a hood containing means forinterchangeably supporting test lenses in alinement with the eye-piece,a chart holder supported within the casing and slidable longitudinallythereof in alinement with the eye-piece, and a scale for indicating thedistance of the chart holder from the eye-piece.

21. An optical instrument of the class described comprising a tubularcasing having an eye-piece at one end, means for supporting test lensesin alinement with the eyepiece, a chart holder guided to operate longitudinally within the casing in alinement with the eye-piece, and anoperating rod connected to the chart holder and provided withgraduations for indicating the distance of the chart from the eye-piece.

22. An optical instrument of the class de scribed comprising a tubularcasing having an eye-piece at one end, means for supporting test lensesin cooperative relation with the eyepiece, a chart holder mounted withinthe casing and in alinement with the eyepiece, a ring gear carryingtherewith a rotatable pointer mounted on the chart holder and adapted tocooperate with a chart thereon, and an operating shaft operativelyconnected to the ring gear and operable from the exterior of theinstrument.

28. An optical instrument of the class described comprising a maintubular section provided with an eye-piece, and means for supportingtest lenses in cooperative relation therewith, an extension tubularsection adapted to detachably fit the rear end of the 100 main section,means for supporting a chart within the extension section, a pair ofangularly arranged sockets formed on the main and extension sections,and an illuminating device having a sleeve adapted to inter- 105changeably fit either of the said sockets.

24. An optical instrument of the class described comprising a tubularcasing having an eye-piece at one end, means for supporting test lensesin cooperative relation t-here- 110 with, a cover fitting the back ofsaid casing and having an observation aperture therein,

a chart holder mounted in the casing between the eye-piece and cover andhaving an aperture in alinement with the eye-piece 115 and theobservation aperture in the cover, and an illuminating device arrangedat one side of the casing and adapted to project a beam of light inalinement with the observation aperture in the cover.

25. An optical instrument of the class described comprising a suitablecasing, a chart holder arranged toward one end thereof, and a hoodmounted at that end of the casing opposite to the chart holder andhaving a 125 portion adapted to fit the face of the patient, the hoodbeing provided with lens holders arranged one behind the other and openat the top of the hood to interchangeably receive and support testlenses.

26. An optical instrument of the class described comprising a suitablecasing adapted to support a chart therein, a hood mounted on one end ofthe casing in operative position with respect to said chart and havingeye-pieces to receive the eyes of the patient, a pair of lens holdersmounted in alinement with each eye-piece, and a rotatable lens holdermounted in alinement with the lens holders first mentioned and havingmeans operable from the exterior of the hood for rotating such rotatablelens holder to adjust the angular position thereof.

27. An optical instrument of the class described comprising a tubularcasing having an eye-piece at one end, means for supporting test lensesin cooperative relation with the eye-piece, a chart holder adapted to bemounted within the casing and having a chart adapted to be arranged inthe line of vision with said eye-piece, a rotatable ring gear carrying apointer mounted on the chart holder and adapted to cooperate with anastigmatic chart thereon, arid means cooperating with said ring gear foradjusting said pointer and indicating the position thereof at theexterior of the instrument casing.

28. An optical instrument of the class described comprising a tubularcasing having an eye-piece at one end, means for supporting test lensesin cooperative relation with the eye-piece, a chart holder adapted to bemounted within the instrument casing, a pair of rollers mounted thereonand having a chart-carrying strip adapted to position the charts thereonin alinement with the eyepiece, and means for operating said strip fromthe exterior of the instrument casing.

29. An optical instrument of the class described comprising a tubularcasing having i a hood arranged at one end thereof and adapted toreceive the face of the patient, and a hood mounted at the opposite endof the casing and adapted to receive the face of the operator, saidhoods being provided with lens holders adapted to receive lenses tocorrect the refractive errors of the eyes of the patient and operator.

80. An optical instrument of the class described comprising a suitablecasing, a hood mounted to slide transversely of the axis of the casingand having lens holders which are adapted to occupy either a centralposition for binocular vision or a posit-ion at either side thereof soas to bring either eye into the line of vision, and catches for retainingthe hood in either of the said positions.

81. An optical instrument of the class described comprising a tubularcasing, an eyepiece at one end thereof adapted to be arranged inalinement with the eye of the patient, a cap removably attached to theopposite end of the instrument and having a hood attached thereto toreceive the face of the operator, a holder formed in said cap adapted toreceive a retinoscope or ophthalmoscope, and means for supporting anilluminating device in cooperative relation to said holder.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

MARK V. GANTT.

\Vitnesses:

H. G. I'IALL, J. J. JENNINGS.

